I don't know much about this diet, but it does sound like nonsense. Eating 500kcals per day is not a fast is it! It's just eating not very much. I think if you;re gonna do it, don't eat on your fast days. It will probably take a week or so for your body to adjust to the fact its got to use its own reserves for fuel.

But if you just want to stay at a healthy weight then the best way is to eat clean and ride your bike fairly hard for an hour or two every day of the week, or as much as you can. The added bonus is you get really fit!

I can't imagine what it'd be like only taking in 500 calories in a day, you must be lethargic to the point of stationary.

Don't imagine it - try it for a fortnight. you might be surprised? It's not 500 cals per day, it's 500 cals for a day, two days a week. You won't die, my bet is that you'll feel hungry, probably about 2 in the afternoon, then it'll pass and you'll be OK once you've had your dinner.

I don't know much about this diet, but it does sound like nonsense. Eating 500kcals per day is not a fast is it! It's just eating not very much. I think if you;re gonna do it, don't eat on your fast days. It will probably take a week or so for your body to adjust to the fact its got to use its own reserves for fuel.

Excellent work David. "I don't know anything about it, but that qualifies me to say why it isn't correct and how I can make it better"

Again - maybe do a bit of reading up on it BEFORE rubbishing it.

In fact - Has anyone that has rubbished the 5:2 on this thread actually read any of the books / articles on it, much less actually tried it?

Maybe some if the smartarses rubbishing the various diets, 5:2 in particular, could give their qualifications and some justifications, so those of us who have actually read a bit about it and are interested in the physiological aspect of weight loss could assess the merits of their criticism.

Thanks in advance and apologies for repeating much of what theotherjonv said ^^^^ but I get a bit tired of people giving simplistic glib answers without anything relevant to back up their comments.

ok well I lost about 11 stone (yes I was huge, this was before I was properly into biking) without any kind of fad or special diet - just cutting down portions, not eating crap and riding my bike every day. It's just the last bits that are harder to shift and require you to be more strict I think. But I don't fast or anything because I know it won't last and I'll be miserable on the fast days, just eating even cleaner and working out harder! Slow progress but progress nonetheless. Like I said I tried the low carb stuff and whilst it helped me get over a plateau it stalled again recently and it wasn't sustainable for the amount of biking I want to do.

So yes, the "eat less move more" lifestyle does work, quite well apparently.

No. It's repetitive and boring.
Maybe some if the smartarses rubbishing the various diets, 5:2 in particular, could give their qualifications and some justifications, so those of us who have actually read a bit about it and are interested in the physiological aspect of weight loss could assess the merits of their criticism.

Thanks in advance.

OK I will go into more detail limit alcohol consumption to bare minimum or even better go teetotal. A lot of eating habits are psychological so looking at what drives your bad eating habbits could be worth a crack or improving your overall mental wellbeing. Perhaps going pescetarian,vegi or even vegan could help limit the number of unhealthy foods consumed. Half way through writing this just looked at what the NHS says on the 5:2 diet. http://www.nhs.uk/news/2013/01January/Pages/Does-the-5-2-intermittent-fasting-diet-work.aspx

Says there is limited evidence that it works and suggests the following.

eating a healthy balanced diet with at least five portions of fruit and vegetables a day

taking regular exercise

drinking alcohol in moderation

[EDIT]Some of my colleagues find those calorie counter apps really good, I have a steps app that encourages me to walk more.

That link made me chuckle. This paragraph in particular"It should be stressed that our assessment of the evidence was confined to entering a number of keywords into Google Scholar and then looking at a small number of studies which we felt would be useful to explore further.

The thing that people seem to always miss on these threads is who you are and from where you are starting.

If you're an obese pie stuffing slob, then eat less move more is indeed far better than some magic pill diet that you think is going to do all the hard work for you.

If you're a casual sportsperson with a few lbs and a few indulgences, then, eating less and moving more could still work - become a bit less casual and indulge less.

However if you're training for a specific goal and already train and eat well, then there may be certain ways to maniuplate your metabolism to lose more weight and/or get a training benefit.

In all of those cases though, understanding how your body actually works beyond the oversimplistic ELMM (and it is oversimplistic, that's clear if you read a bit more) may well achieve quicker and more permanent results. Depending on your personality and brain of course.

In fact - Has anyone that has rubbished the 5:2 on this thread actually read any of the books / articles on it, much less actually tried it?

It's hard to imagine a book on the 5:2 diet. Wouldn't it be more like a pamphlet? A couple of sentences would probably do tbh.

The lack of pseudoscientific posturing to the actual diet is part of the appeal of the 5:2. I guess there must be attendant mumbo jumbo if someone actually has written a book about it, but the diet itself is refreshingly straightforward. The 5/2 ratio, along with the calorie recommendations, have prob been pulled out of someone's ringpiece. But in doing so they have hit upon a neat psychological approach that I'm finding works for me.

Don't imagine it - try it for a fortnight. you might be surprised? It's not 500 cals per day, it's 500 cals for a day, two days a week. You won't die, my bet is that you'll feel hungry, probably about 2 in the afternoon, then it'll pass and you'll be OK once you've had your dinner.

If you knew me you'd know that I eat more than 500 cals before lunch - and I'm hungry at lunch

Thread update.....
6 weeks on and I've lost nigh on a stone so it's working for me at the mo. More aware of what I'm eating and food values which helps. Some weeks I've done 3 days fasting when I've overdone it with takeaways on the 'normal' days.

As always on any forum there is debate and polarised opinions. All I can add to the thread is that I watched the original Horizon prog and thought it a balanced and well presented piece of research. It did not hype any books or products at the time as far as I recall. What it did suggest was that with a permanent change of lifestyle you could achieve :-

Weight loss....tick
A change in various indicators that would lead to a reduced risk of Type 2 Diabetes and cholestoral heart disease....tick

The program showed research to prove this in the presenter himself and apparently the NHS agrees as well....So either try it and tell your results or shut up.

Having tried it (and stuck to it other than on my summer hols) I can confirm that you do loose weight and it's not too hard to stick to..Don't know if I've had any improvements in cholestoral or reduced my diabetes risks as I hadn't had a test before but like a previous poster said ...If I have then it's a bonus (and it was a major part of my decision to try the diet in the first place) but if not then I've lost weight anyway.

If you're hungry, eat more food. Teh 500cal is not a scientifically demonstrated optimal number, but an arbitrary one chosen for calorie deficit. Nothing wrong with picking 600 or 700 imho.
It was a TV show, not science, even if they get a presenter with a medical doctorate to undergo the "diet".

Most of those I know doing this are hungry, but use willpower and other techniques to forget about the hunger, and eventually get used to the hunger.

Tried it, lost no weight, but just ended up compensating the next day. There are other ways to lose weight.

Given that most who do this diet claim, or indeed are, more aware of the calorific content of their food, what would happen if you dropped each days calory intake by 500cals but didn't have fast days? Weekly intake would drop but be the same as on the 5:2 "diet".

My brother did a charity fast once. No food except bread and water for 24 hours. Started it after dinner one evening. Finished it just before dinner the next evening. Had sarnies for lunch. So in effect was a normal day, apart from moving 2 dinners slightly earlier/later, and skipping breakfast.

As someone who eats large amounts, struggles with portion control, makes awesome pies and curries, loves little more than a plate full of pasta. This diet plan, works for me, sometimes I follow it more tightly than others, I find a can fast at work pretty easily as the temptation is reduced. As has been said above, eating 'sensibly and healthily' all the damn time just means I'm made to feel bad for every nice thing I have, EVER. And frankly, **** that! Plus sticking to it for more than a couple of months is really hard to do. But if I am left to my own devices I put on 2 stone so something is needed. It sounds a lot like it works for otherS in a similar way. Found my diet.

However if you're training for a specific goal and already train and eat well, then there may be certain ways to manipulate your metabolism to lose more weight and/or get a training benefit.

I don't necessarily disagree, but every cycling biography I've read (when they go into such detail) seems to revolve around weighing portions, timing training so on bike food is taken over meal times (skipping a meal) and essentially ENSURING (and that's the point, the bit I miss) a slight calorie deficit. They also all seem as neo pros to live on the cheapest carb rich foods they could get their hands on.

I've done the leangains style 8 hour window one before, never really thought of it as a 'diet' though, just a way to easily restrict my calories to a reasonable level for my fairly sedate daily life.

In fact, it worked so well since I've stopped I'm hungry all the time and I've put a stone on. Think I'll be going back on it from tomorrow seeing as I finished the last of my granola off this morning.

The problem (especially for people like me who eat with the family) with following diets like pro cyclists is that they can eat what they want to buy for themselves and then have the time/will to train for hours a day. I could probably lose weight eating pasta three times a day if I was out riding for 5 hours+ a day. But after leaving the house for work at 7 in the morning then getting back at 7 at night then entertaining the kids for an hour or two it doesn't leave a fat lot of time to ride.

Fasting diets are great if you need to restrict calories very low for office worker types that don't get chance to do huge training milages. For example, for me to lose any weight, I have to restrict my calories down to below 1500 for the day, that's pretty hard if you have breakfast, lunch and then dinner with a family of skinny feckers

I hear what you're saying (my situation too) but I was more illustrating that they seem to go from some silly low fat % and weight to even lower simply by creating a calorie deficit, rather than anything more elaborate.

I reckon 99% of my problems are down to just not being obsessive enough about the balance, and possibly not really being sure about how many calories the tipping point is at for me - 2500 calories is as arbitrary as 220 - Age for HR obviously.

I've been on the Paleo diet for two months now and can thoroughly encourage it. The amount of research and references to peer reviewed articles is astounding. Backed by Joe Friel too, so ideal for athletes. It's made a big difference to how hungry I am, and I'm in the form of my life currently.

They also all seem as neo pros to live on the cheapest carb rich foods they could get their hands on.

That's the old way of doing things, a neo pro often had to fend for himself. And generally cheap foods are carb rich, rather than the other way around.

If you followed a Team Sky neo pro, who will actually have access to the teams resources, dietitians etc will be on a carefully controlled diet which will contain a lot of protein and if they are tyring to lose weight will be in calorie deficit.

It's probably not advisable for a pro cyclist who trains 5/6 times a week to do the 5:2 diet as on the fast days they will have very extreme calorie deficit; but for one of us regular people who can maybe only exercise twice a week it seems like a very simple, neat way to ensure we are in calorie deficit and being hungry twice a week won't do us any harm.

@ Brassneck I agree too, at the end of the day, it's all simple deficit whatever method you use, even the paleo diet, you just end up not getting the cravings and stuff becuase 1. your'e committed to not eating mars bars and 2. meat and protein is more filling and less calorie dense/lower GI

Where the pro cyclists have the edge is that a 500 calorie deficit on 5000 calories a day is much easier to manage hunger wise than 500 calories of 2000.

Also sitting in an office all day makes me want to eat/drink/kill myself.

Any 'fad diet' that consists of eating less 'proper food' rather than watered down corn syrup and cayenne pepper is fine by me, they're just a nice set of rules the keep you on the path. It's the same as having a workout plan rather than just going to the gym and doing whatever you feel like.